internal/exectracetest: port database/sql test to the new parser

[nsrip-dd]

What does this PR do?

Port the contrib/database/sql execution tracer test to use the new
golang.org/x/exp/trace parser. The test is slightly cleaned up, but for
the most part covers the same logic as its predecessor (see #2060). The
primary difference is that, rather than hooking into a mock database/sql
driver, we use a real one (sqlite3). To simulate a slow operation, the
test registers a sleep function and also sleeps on connection. The
purpose of this is to ensure, where we can, the tracer tasks cover the
whole operation and not just the end of it. We no longer hook into
every operation, though, so we drop some time assertions.

Motivation

To ensure that our execution tracing integration works properly with
contrib/database/sql, and that it is tested in a way that will keep up with
future changes to the execution tracer.

Reviewer's Checklist

• Changed code has unit tests for its functionality at or near 100% coverage.
• System-Tests covering this feature have been added and enabled with the va.b.c-dev version tag.
• There is a benchmark for any new code, or changes to existing code.
• If this interacts with the agent in a new way, a system test has been added.
• Add an appropriate team label so this PR gets put in the right place for the release notes.
• Non-trivial go.mod changes, e.g. adding new modules, are reviewed by @DataDog/dd-trace-go-guild.

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[pr-commenter]

Benchmarks

Benchmark execution time: 2024-07-16 18:54:17

Comparing candidate commit 994a9eb in PR branch nick.ripley/port-sql-trace-test-parser with baseline commit d3a6549 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 47 metrics, 0 unstable metrics.