[MIPS] Remove function QuietNaN.

After 54a18895, Bug:7464, the permission of the page is read only, but this function need write permission.

Since this function is not used, just remove it.

Change-Id: I5a5976ab773bd808920893bbd2e3d9796e89e804
Reviewed-on: https://chromium-review.googlesource.com/c/1490813Reviewed-by: Predrag Rudic <prudic@wavecomp.com>
Commit-Queue: Yu Yin <xwafish@gmail.com>
Cr-Commit-Position: refs/heads/master@{#59995}

src/mips/assembler-mips.cc

@@ -4051,14 +4051,6 @@ Address Assembler::target_address_at(Address pc) {
 }
 
 
-// MIPS and ia32 use opposite encoding for qNaN and sNaN, such that ia32
-// qNaN is a MIPS sNaN, and ia32 sNaN is MIPS qNaN. If running from a heap
-// snapshot generated on ia32, the resulting MIPS sNaN must be quieted.
-// OS::nan_value() returns a qNaN.
-void Assembler::QuietNaN(HeapObject object) {
-  HeapNumber::cast(object)->set_value(std::numeric_limits<double>::quiet_NaN());
-}
-
 // On Mips, a target address is stored in a lui/ori instruction pair, each
 // of which load 16 bits of the 32-bit address to a register.
 // Patching the address must replace both instr, and flush the i-cache.

src/mips/assembler-mips.h

@@ -266,8 +266,6 @@ class V8_EXPORT_PRIVATE Assembler : public AssemblerBase {
   // of that call in the instruction stream.
   inline static Address target_address_from_return_address(Address pc);
 
-  static void QuietNaN(HeapObject nan);
-
   // This sets the branch destination (which gets loaded at the call address).
   // This is for calls and branches within generated code.  The serializer
   // has already deserialized the lui/ori instructions etc.

src/mips64/assembler-mips64.cc

@@ -4301,14 +4301,6 @@ Address Assembler::target_address_at(Address pc) {
 }
 
 
-// MIPS and ia32 use opposite encoding for qNaN and sNaN, such that ia32
-// qNaN is a MIPS sNaN, and ia32 sNaN is MIPS qNaN. If running from a heap
-// snapshot generated on ia32, the resulting MIPS sNaN must be quieted.
-// OS::nan_value() returns a qNaN.
-void Assembler::QuietNaN(HeapObject object) {
-  HeapNumber::cast(object)->set_value(std::numeric_limits<double>::quiet_NaN());
-}
-
 // On Mips64, a target address is stored in a 4-instruction sequence:
 //    0: lui(rd, (j.imm64_ >> 32) & kImm16Mask);
 //    1: ori(rd, rd, (j.imm64_ >> 16) & kImm16Mask);

src/mips64/assembler-mips64.h

@@ -267,8 +267,6 @@ class V8_EXPORT_PRIVATE Assembler : public AssemblerBase {
 
   static void JumpLabelToJumpRegister(Address pc);
 
-  static void QuietNaN(HeapObject nan);
-
   // This sets the branch destination (which gets loaded at the call address).
   // This is for calls and branches within generated code.  The serializer
   // has already deserialized the lui/ori instructions etc.