[Interpreter] Refactor bytecode generator test suite.

test/cctest/interpreter/bytecode_expectations/DoExpression.golden

+#
+# Autogenerated by generate-bytecode-expectations
+#
+
+---
+pool type: string
+execute: yes
+wrap: yes
+do expressions: yes
+
+---
+snippet: "
+  var a = do { }; return a;
+"
+frame size: 2
+parameter count: 1
+bytecode array length: 6
+bytecodes: [
+  B(StackCheck),
+  B(Ldar), R(0),
+  B(Star), R(1),
+  B(Return),
+]
+constant pool: [
+]
+handlers: [
+]
+
+---
+snippet: "
+  var a = do { var x = 100; }; return a;
+"
+frame size: 3
+parameter count: 1
+bytecode array length: 11
+bytecodes: [
+  B(StackCheck),
+  B(LdaSmi8), U8(100),
+  B(Star), R(1),
+  B(LdaUndefined),
+  B(Star), R(0),
+  B(Star), R(2),
+  B(Return),
+]
+constant pool: [
+]
+handlers: [
+]
+
+---
+snippet: "
+  while(true) { var a = 10; a = do { ++a; break; }; a = 20; }
+"
+frame size: 2
+parameter count: 1
+bytecode array length: 26
+bytecodes: [
+  B(StackCheck),
+  B(StackCheck),
+  B(LdaSmi8), U8(10),
+  B(Star), R(1),
+  B(ToNumber),
+  B(Inc),
+  B(Star), R(1),
+  B(Star), R(0),
+  B(Jump), U8(12),
+  B(Ldar), R(0),
+  B(Star), R(1),
+  B(LdaSmi8), U8(20),
+  B(Star), R(1),
+  B(Jump), U8(-21),
+  B(LdaUndefined),
+  B(Return),
+]
+constant pool: [
+]
+handlers: [
+]
+