Issue #387 pointed out that integer float data is printed incorrectly, such
that it is not parsed correctly by the Go assembler. Specifically, integer
values need the decimal point, otherwise they will be treated as integers. For
example, 1 must be represented as `$(1.)` or `$(1.0)` to be parsed correctly.
This PR fixes that problem and adds a regression test. The root of the
problem was that the formatting verb `%#v` does not have the right behavior
for integers. We fix it by deferring to custom `String()` function for the
float operand types.
Fixes#387Closes#388
Commit 759be3dad9 bumped our Go
requirement to 1.18 which allows us to drop support for old-style
`+build` tags. This change runs `go fix ./...` to remove them, and
updates some remaining code generators that produced `+build` lines.
