Fix gofmt errors for uppercase exponents

Go 1.13 unified exponents to be lowercase
https://golang.org/doc/go1.13#gofmt

Author: abitrolly

grumpy-runtime-src/runtime/complex_test.go

@@ -412,7 +412,7 @@ func TestComplexPos(t *testing.T) {
 	cases := []invokeTestCase{
 		{args: wrapArgs(complex(0, 0)), want: NewComplex(complex(0, 0)).ToObject()},
 		{args: wrapArgs(complex(42, -0.1)), want: NewComplex(complex(42, -0.1)).ToObject()},
-		{args: wrapArgs(complex(-1.2, 375E+2)), want: NewComplex(complex(-1.2, 37500)).ToObject()},
+		{args: wrapArgs(complex(-1.2, 375e+2)), want: NewComplex(complex(-1.2, 37500)).ToObject()},
 		{args: wrapArgs(complex(5, math.NaN())), want: NewComplex(complex(5, math.NaN())).ToObject()},
 		{args: wrapArgs(complex(math.Inf(1), 0.618)), want: NewComplex(complex(math.Inf(1), 0.618)).ToObject()},
 	}

grumpy-runtime-src/runtime/float_test.go

@@ -307,7 +307,7 @@ func TestFloatRepr(t *testing.T) {
 		{args: wrapArgs(1e+6), want: NewStr("1000000.0").ToObject()},
 		{args: wrapArgs(1e+15), want: NewStr("1000000000000000.0").ToObject()},
 		{args: wrapArgs(1e+16), want: NewStr("1e+16").ToObject()},
-		{args: wrapArgs(1E16), want: NewStr("1e+16").ToObject()},
+		{args: wrapArgs(1e16), want: NewStr("1e+16").ToObject()},
 		{args: wrapArgs(1e-6), want: NewStr("1e-06").ToObject()},
 		{args: wrapArgs(math.Inf(1)), want: NewStr("inf").ToObject()},
 		{args: wrapArgs(math.Inf(-1)), want: NewStr("-inf").ToObject()},