Test that floating point constants resolve to type "float".

Currently 6g seems to resolve them to type "double".

R=ken,r
DELTA=30  (30 added, 0 deleted, 0 changed)
OCL=16132
CL=16152

test/bugs/bug109.go

+// $G $D/$F.go || echo BUG: should compile
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+func f(a float) float {
+	e := 1.0;
+	e = e * a;
+	return e;
+}
+
+/*
+6g bugs/bug109.go
+bugs/bug109.go:5: illegal types for operand: MUL
+        (<float64>FLOAT64)
+        (<float32>FLOAT32)
+bugs/bug109.go:5: illegal types for operand: AS
+        (<float64>FLOAT64)
+bugs/bug109.go:6: illegal types for operand: RETURN
+        (<float32>FLOAT32)
+        (<float64>FLOAT64)
+*/

test/golden.out

@@ -168,6 +168,17 @@ BUG: errchk: command succeeded unexpectedly:  6g bugs/bug107.go
 bugs/bug108.go:4: stupid shift: 1025
 BUG: errchk: command succeeded unexpectedly:  6g bugs/bug108.go
 
+=========== bugs/bug109.go
+bugs/bug109.go:5: illegal types for operand: MUL
+	(<float64>FLOAT64)
+	(<float32>FLOAT32)
+bugs/bug109.go:5: illegal types for operand: AS
+	(<float64>FLOAT64)
+bugs/bug109.go:6: illegal types for operand: RETURN
+	(<float32>FLOAT32)
+	(<float64>FLOAT64)
+BUG: should compile
+
 =========== fixedbugs/bug016.go
 fixedbugs/bug016.go:7: overflow converting constant to <uint32>UINT32