[test] Move cctest/test-disasm-riscv64 to unittests/assembler/

... disasm-riscv64-unittest.

Bug: v8:12781
Change-Id: I0d4c0ffbda5757db6a6b906e9f51ce28bc5f6f11
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3676641
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80833}

test/cctest/BUILD.gn

@@ -323,7 +323,6 @@ v8_source_set("cctest_sources") {
   } else if (v8_current_cpu == "riscv64") {
     sources += [  ### gcmole(arch:riscv64) ###
       "test-assembler-riscv64.cc",
-      "test-disasm-riscv64.cc",
       "test-helper-riscv64.cc",
       "test-macro-assembler-riscv64.cc",
       "test-simple-riscv64.cc",

test/unittests/BUILD.gn

@@ -525,6 +525,7 @@ v8_source_set("unittests_sources") {
     ]
   } else if (v8_current_cpu == "riscv64") {
     sources += [
+      "assembler/disasm-riscv64-unittest.cc",
       "assembler/turbo-assembler-riscv64-unittest.cc",
       "compiler/riscv64/instruction-selector-riscv64-unittest.cc",
     ]