[Interpreter] Refactor bytecode generator test suite.

test/cctest/interpreter/StringConstants.golden

Index: test/cctest/interpreter/StringConstants.golden
diff --git a/test/cctest/interpreter/StringConstants.golden b/test/cctest/interpreter/StringConstants.golden
new file mode 100644
index 0000000000000000000000000000000000000000..110cd8c372f6eebddaf199e3794e115c28d34490
--- /dev/null
+++ b/test/cctest/interpreter/StringConstants.golden
@@ -0,0 +1,65 @@
+#
+# Autogenerated by generate-bytecode-expectations
+#
+
+---
+pool type: string
+execute: yes
+wrap: yes
+
+---
+snippet: "
+  return \"This is a string\";
+"
+frame size: 0
+parameter count: 1
+bytecodes: [
+  B(StackCheck),
+  B(LdaConstant), U8(0),
+  B(Return),
+]
+constant pool: [
+  "This is a string",
+]
+handlers: [
+]
+
+---
+snippet: "
+  var a = \"First string\"; return \"Second string\";
+"
+frame size: 1  # in multiples of sizeof(void*)
+parameter count: 1
+bytecodes: [
+  B(StackCheck),
+  B(LdaConstant), U8(0),
+  B(Star), R(0),
+  B(LdaConstant), U8(1),
+  B(Return),
+]
+constant pool: [
+  "First string",
+  "Second string",
+]
+handlers: [
+]
+
+---
+snippet: "
+  var a = \"Same string\"; return \"Same string\";
+"
+frame size: 1  # in multiples of sizeof(void*)
+parameter count: 1
+bytecodes: [
+  B(StackCheck),
+  B(LdaConstant), U8(0),
+  B(Star), R(0),
+  B(LdaConstant), U8(0),
+  B(Return),
+]
+constant pool: [
+  "Same string",
+]
+handlers: [
+]
+