Add test case for expansions changing context

Author: Rangi42

test/asm/expansions-change-context.asm

@@ -0,0 +1,23 @@
+def string_start equs "println \"hello"
+string_start world"
+
+def triple_string_start equs "println \"\"\"multi"
+triple_string_start;ple
+line
+strings"""
+
+def cond_start equs "if 0\nprintln \"false\"\nelif"
+cond_start 1
+  println "true"
+else
+  println "nan"
+endc
+
+def loop_start equs "rept 3\nprintln"
+loop_start "lol"
+endr
+
+def macro_start equs "macro foo\nprintln"
+macro_start \1
+endm
+  foo 42

test/asm/expansions-change-context.out

@@ -0,0 +1,9 @@
+hello world
+multi;ple
+line
+strings
+true
+lol
+lol
+lol
+$2A