[Interpreter] Refactor bytecode generator test suite.

test/cctest/interpreter/RegExpLiterals.golden

+#
+# Autogenerated by generate-bytecode-expectations
+#
+
+---
+pool type: string
+execute: yes
+wrap: yes
+
+---
+snippet: "
+  return /ab+d/;
+"
+frame size: 0
+parameter count: 1
+bytecodes: [
+  B(StackCheck),
+  B(CreateRegExpLiteral), U8(0), U8(0), U8(0),
+  B(Return),
+]
+constant pool: [
+  "ab+d",
+]
+handlers: [
+]
+
+---
+snippet: "
+  return /(\\w+)\\s(\\w+)/i;
+"
+frame size: 0
+parameter count: 1
+bytecodes: [
+  B(StackCheck),
+  B(CreateRegExpLiteral), U8(0), U8(0), U8(2),
+  B(Return),
+]
+constant pool: [
+  "(\x5cw+)\x5cs(\x5cw+)",
+]
+handlers: [
+]
+
+---
+snippet: "
+  return /ab+d/.exec('abdd');
+"
+frame size: 3  # in multiples of sizeof(void*)
+parameter count: 1
+bytecodes: [
+  B(StackCheck),
+  B(CreateRegExpLiteral), U8(0), U8(0), U8(0),
+  B(Star), R(1),
+  B(LoadIC), R(1), U8(1), U8(3),
+  B(Star), R(0),
+  B(LdaConstant), U8(2),
+  B(Star), R(2),
+  B(Call), R(0), R(1), U8(2), U8(1),
+  B(Return),
+]
+constant pool: [
+  "ab+d",
+  "exec",
+  "abdd",
+]
+handlers: [
+]
+