Allow resume in nosuspend scope

Resuming a suspended async function call is actually a synchronous
operation.

This commit removes the compiler code which generates the error and
updates the relevant test case.

test/compile_errors.zig

@@ -1029,7 +1029,6 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
     , &[_][]const u8{
         "tmp.zig:3:21: error: async call in nosuspend scope",
         "tmp.zig:4:9: error: suspend in nosuspend scope",
-        "tmp.zig:5:9: error: resume in nosuspend scope",
     });
 
     cases.add("atomicrmw with bool op not .Xchg",