PPC: [intrinsics] Remove the %_IsDate intrinsic.

Port 0d595bb0

Original commit message:
    It's fine to only have the runtime call here, as it's only used in the
    debug mirror.

R=bmeurer@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1707683002

Cr-Commit-Position: refs/heads/master@{#34085}

src/full-codegen/ppc/full-codegen-ppc.cc

@@ -3145,28 +3145,6 @@ void FullCodeGenerator::EmitValueOf(CallRuntime* expr) {
 }
 
 
-void FullCodeGenerator::EmitIsDate(CallRuntime* expr) {
-  ZoneList<Expression*>* args = expr->arguments();
-  DCHECK_EQ(1, args->length());
-
-  VisitForAccumulatorValue(args->at(0));
-
-  Label materialize_true, materialize_false;
-  Label* if_true = nullptr;
-  Label* if_false = nullptr;
-  Label* fall_through = nullptr;
-  context()->PrepareTest(&materialize_true, &materialize_false, &if_true,
-                         &if_false, &fall_through);
-
-  __ JumpIfSmi(r3, if_false);
-  __ CompareObjectType(r3, r4, r4, JS_DATE_TYPE);
-  PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  Split(eq, if_true, if_false, fall_through);
-
-  context()->Plug(if_true, if_false);
-}
-
-
 void FullCodeGenerator::EmitOneByteSeqStringSetChar(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK_EQ(3, args->length());