gnovm/pkg/transpiler: mangled imports in Gno code cause a panic when generating Go code

[odeke-em]

Description

In furtherance of #3087, I am fuzzing and investigating the transpiler and when presented with this Gno program

package A
import(""//"
""/***/)

Passing it into the transpiler results in this panic

panic: invalid line number 5 (should be < 5) [recovered]
	panic: invalid line number 5 (should be < 5)

goroutine 26 [running]:
github.com/gnolang/gno/gnovm/pkg/transpiler.Transpile.func1()
	/home/emmanuel/go/src/github.com/gnolang/gno/gnovm/pkg/transpiler/transpiler.go:131 +0xae
panic({0xb30640?, 0xc0001246c0?})
	/home/emmanuel/go/src/go.googlesource.com/go/src/runtime/panic.go:787 +0x132
go/token.(*File).MergeLine(0xc00028e300, 0x63?)
	/home/emmanuel/go/src/go.googlesource.com/go/src/go/token/position.go:157 +0x1a8
go/ast.sortSpecs(0xc00025e080, 0xc0006c4dc0, {0xc000126e80, 0x2, 0x2})
	/home/emmanuel/go/src/go.googlesource.com/go/src/go/ast/import.go:210 +0xa54
go/ast.SortImports(0xc00025e080, 0xc0006c4dc0)
	/home/emmanuel/go/src/go.googlesource.com/go/src/go/ast/import.go:40 +0x5a7
go/format.Node({0xe56460, 0xc0006a5740}, 0xc00025e080, {0xb6d720?, 0xc0006c4be0?})
	/home/emmanuel/go/src/go.googlesource.com/go/src/go/format/format.go:81 +0x286
github.com/gnolang/gno/gnovm/pkg/transpiler.Transpile({0xc00044f000, 0x1f}, {0xc2c171, 0x3}, {0xc2d99e, 0x6})
	/home/emmanuel/go/src/github.com/gnolang/gno/gnovm/pkg/transpiler/transpiler.go:134 +0x5ef

where it tried to generate this Go code

// Code generated by github.com/gnolang/gno. DO NOT EDIT.

//go:build gno

//line in.gno:1:1

Expected behaviour

Not a panic

Kindly cc-ing @petar-dambovaliev @moul @jaekwon